Inbred corn line ZS03940

ABSTRACT

Broadly this invention provides inbred corn line ZS03940. The methods for producing a corn plant by crossing the inbred line ZS03940 are encompassed by the invention. Additionally, the invention relates to the various parts of inbred ZS03940 including culturable cells. This invention relates to hybrid corn seeds and plants produced by crossing the inbred line ZS03940 with at least one other corn line.

FIELD OF THE INVENTION

This invention is in the field of corn breeding, specifically relating to an inbred corn line designated ZS03940.

BACKGROUND OF THE INVENTION

The original maize plant was indigenous to the Western Hemisphere. The plants were weedlike and only through the efforts of early breeders was a cultivated crop species developed. The physical traits of maize are such that self pollination or cross pollination can occur. Each plant has a separate male and female flower, the tassel and ear, respectively. Natural pollination occurs when wind transfers pollen from tassel to the silks on the corn ears. This type of pollination contributed to the wide variation of maize varieties present in the Western Hemisphere.

The development of a planned breeding program for maize only occurred in the last century. Originally, maize was an open pollinated variety having heterogeneous genotypes. The maize farmer selected uniform ears from the yield of these genotypes and reserved them for planting the next season. The result was a field of maize plants that were segregating for a variety of traits. This type of maize selection lead to at most incremental increases in seed yield.

Large increases in seed yield were the result of the development of hybrid corn varieties in planned breeding programs. Hybrids were developed by selecting corn lines and selfing these lines for several generations to develop homozygous pure inbred lines and crossing selected inbred lines with unrelated inbred lines to produce hybrid progeny (F1). Inbred lines can be difficult to produce since the inbreeding process in corn decreases the vigor. However, when two inbred lines are crossed, the hybrid plant evidences greatly increased vigor compared to open pollinated segregating maize plants. An important factor of the homozygosity and the homogeneity of the inbred lines is that the hybrid from any cross will always be the same, and can be reproduced.

The ultimate objective of the commercial maize seed companies is to produce high yielding, agronomically sound plants which perform well in certain regions or areas of the Corn Belt. To produce these types of hybrids, the companies must develop inbreds which carry needed traits into the hybrid combination. Hybrids are not uniformly adapted for the Corn Belt, but are specifically adapted for regions of the Corn Belt. Northern regions of the Corn Belt require shorter season hybrids than do southern regions of the Corn Belt. Hybrids that grow well in Colorado and Nebraska soils may not flourish in rich Illinois soil Thus, a variety of major agronomic traits are important in hybrid combination for the various Corn Belt regions, and have an impact on hybrid performance.

Inbred line development and hybrid testing have been emphasized in the past half century in commercial maize production as a means to increase hybrid performance. Inbred development is usually done by pedigree selection. Pedigree selection can be selection in an F₂ population produced from a planned cross of two genotypes (often elite inbred lines), or selection of progeny of synthetic varieties, open pollinated, composite, or backcross populations. This type of selection is effective for highly inheritable traits, but other traits, for example, yield requires replicated test crosses at a variety of stages for accurate selection.

Maize breeders select for a variety of traits in inbreds that impact hybrid performance along with selecting for acceptable parental traits. Such traits include yield potential in hybrid combination; dry down; maturity; grain moisture at harvest; greensnap; resistance to root lodging; resistance to stalk lodging; grain quality; disease and insect resistance; ear and plant height; performance in different soil types such as: low level of organic matter, clay, sand, black, high pH, low pH; performance in: wet environments, drought environments, and no tillage conditions. These traits appear to be governed by a complex genetic system that makes selection and breeding of an inbred line extremely difficult. Even if an inbred, in hybrid combination, has excellent yield (a desired characteristic), it may not be useful because it fails to have acceptable parental traits such as seed yield, seed size, pollen production, good silks, plant height, etc.

To illustrate the difficulty of breeding and developing inbred lines, the following example is given. Two inbreds compared for similarity of 29 traits differed significantly for 18 traits between the two lines. If 18 simply inherited single gene traits were polymorphic with gene frequencies of 0.5 in the parental lines, and assuming independent segregation (as would essentially be the case if each trait resided on a different chromosome arm), then the specific combination of these traits as embodied in an inbred would only be expected to become fixed at a rate of one in 262,144 possible homozygous genetic combinations. Selection of the specific inbred combination is also influenced by the specific selection environment on many of these 18 traits which makes the probability of obtaining this one inbred even more remote. Thus, the general procedure of producing a non segregating F₁ generation and self pollinating to produce a F₂ generation that segregates for traits does not easily lead to a useful inbred. Great care and breeder expertise must be used in selection of breeding material to continue to increase yield and agronomics of inbreds and resultant commercial hybrids.

SUMMARY OF THE INVENTION

The present invention relates to an inbred corn line ZS03940. Specifically, this invention relates to plants and seeds of this line. Additionally, this relates to a method of producing hybrid seed corn from this inbred. More particularly, this invention relates to the unique combination of traits in corn line ZS03940.

Generally then, the present invention includes an inbred corn seed designated ZS03940. This seed produces a corn plant.

The invention also includes the tissue culture of regenerable cells of ZS03940 wherein the tissue regenerates plants having the genotype of ZS03940. The tissue culture is selected from the group consisting of leaves, pollen, embryos, roots, root tips, anthers, silk, flowers, kernels, ears, cobs, husks and stalks, and cells and protoplasts thereof.

The invention extends to hybrid seed produced by planting, in pollinating proximity, seeds of corn inbred lines ZS03940 and another inbred line; cultivating corn plants resulting from said planting; preventing pollen production by the plants of one of the inbred lines; allowing natural cross pollinating to occur between said inbred lines; and harvesting seeds produced on plants of the inbred. The hybrid seed produced by hybrid combination of plants of inbred corn seed designated ZS03940 and plants of another inbred line. Hybrid plants grown from this hybrid seed.

The invention further includes a method of hybrid F1 production. A first generation (F1) hybrid corn plant produced by the process of planting, in pollinating proximity, seeds of corn inbred lines ZS03940 and another inbred line; cultivating corn plants resulting from said planting; preventing pollen production by the plants of one of the inbred lines; allowing natural cross pollinating to occur between said inbred lines; harvesting seeds produced on plants of the inbred; and growing a harvested seed.

A tissue culture of the regenerable cells of hybrid plants produced with use of ZS03940 genetic material. A tissue culture of the regenerable cells of the corn plant produced by the method described above.

DEFINITIONS

In the description and examples which follow, a number of terms are used. In order to provide a clear and consistent understanding of the specifications and claims, including the scope to be given such terms, the following definitions are provided.

BL MOIST

The moisture percentage of the grain at black layer, i.e., when 50% of the plants per plot have reached physiological maturity.

COLD GERM

Cold Germ is a measurement of seed germination under cold soil conditions. Data is reported as percent of seed germinating.

ECB

European corn borer a maize eating insect. ECBI is the first brood generation of European corn borers. ECBII is the second generation of European corn borers.

EMERGE

The number of emerged plants per plot (planted at the same seedling rate) collected when plants have two fully developed leaves.

GI

This is a selection index which provides a single quantitative measure of the worth of a hybrid based on four traits. Yield is the primary trait contributing to index values. The GI value is calculated by combining stalk lodging, root lodging, yield and dropped ears according to the attached mathematical formula:

    GI=100+0.5(YLD)-0.9(% STALK LODGE)-0.9(% ROOT LODGE)-2.7(% DROPPED EAR)

GLS

Gray Leaf Spot (Cercospora Zeae) disease rating. This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*

GW

Goss' Wilt (Corynebacterium nebraskense). This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*

HEATP10

The number of Growing Degree Units (GDU's) or heat units required for an inbred line or hybrid to have approximately 10 percent of the plants shedding pollen. This trait is measured from the time of planting. Growing Degree Units are calculated by the Barger Method where the GDU's for a 24 hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimum temperature used is 50° F. For each inbred or hybrid it takes a certain number of GDU's to reach various stages of plant development.

HEATBL

The number of GDU's after planting when approximately 50 percent of the inbred or hybrid plants in a plot have grain which has reached physiological maturity (black layer).

HEATPEEK

The number of GDU's after planting of an inbred when approximately 50 percent of the plants show visible tassel extension.

HEATP50 or HTP50

The number of GDU's required for an inbred or hybrid to have approximately 50 percent of the plants shedding pollen. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.

HEATP90

The number of GDU's accumulated from planting when the last 100 percent of plants in an inbred or hybrid are still shedding enough viable pollen for pollination to occur. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.

HEATS10

The number of GDU's required for an inbred or hybrid to have approximately 10 percent of the plants with silk emergence of at least 0.5 inches. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.

HEATS50 or HTS50

The number of GDU's required for an inbred or hybrid to have approximately 50 percent of the plants with silk emergence of at least 0.5 inches. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.

HEATS90

The number of GDU's required for an inbred or hybrid to have approximately 90 percent of the plants with silk emergence of at least 0.5 inches. Growing Degree Units are calculated by the Barger Method as shown in the HEATP10 definition.

MDMV_(A)

Maize Dwarf Mosaic Virus strain A. The corn is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*

MDMV_(B)

Maize Dwarf Mosaic Virus strain B. This is rated on a 1-9 scale with a "1" being very susceptible and a "9" being very resistant.*

MOISTURE

The average percentage grain moisture of an inbred or hybrid at harvest time.

NLB

Northern Leaf Blight (Exserohilum turcicum) disease rating. This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*

PCT TILLER

The total number of tillers per plot divided by the total number of plants per plot.

PLANT

This term includes plant cells, plant protoplasts, plant cell tissue cultures from which corn plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants or parts of plants, such as embryos, pollen, flowers, kernels, ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silk and the like.

PLANT HEIGHT

The distance in centimeters from ground level to the base of the tassel peduncle.

RM

Predicted relative maturity based on the moisture percentage of the grain at harvest. This rating is based on known set of checks and utilizes standard linear regression analyses and is referred to as the Minnesota Relative Maturity Rating System.

SHED

The volume of pollen shed by the male flower rated on a 1-9 scale where a "1" is a very light pollen shedder, a "4.5" is a moderate shedder, and a "9" is a very heavy shedder.

SLB

Southern Leaf Blight (Bipolaris maydis) disease rating. This is rated on a 1-9 scale with a "1" being very susceptible, and a "9" being very resistant.*

TWT

The measure of the weight of grain in pounds for a one bushel volume adjusted for percent grain moisture.

VIGOR

Visual rating of 1 to 9 made 2-3 weeks post-emergence where a "1" indicates very poor early plant development, and a "9" indicates superior plant development.

WARM GERM

A measurement of seed germination under ideal (warm, moist) conditions. Data is reported as percent of seeds germinating.

YIELD (YLD)

Actual yield of grain at harvest adjusted to 15.5% moisture. Measurements are reported in bushels per acre.

% DROPPED EARS (DE)

The number of plants per plot which dropped their primary ear divided by the total number of plants per plot.

% LRG FLAT

Percentage by weight of shelled corn that passes through a 26/64 inch round screen and a 14/64 inch slot screen, but does not pass through a screen with 20.5/64 inch round openings.

% LRG ROUND

Percentage by weight of shelled corn that passes through a 26/64 inch round screen, but does not pass through a 14/64 inch slot screen or a screen with 20.5/64 inch round openings.

% MED FLAT

Percentage by weight of shelled corn that passes through a 20.5/64 inch round screen and a 13/64 inch slotted screen, but does not pass through a screen with 17/64 inch round openings.

% MED ROUND

Percentage by weight of shelled corn that passes through a 20.5/64 inch round screen, but does not pass through a 13/64 inch slot screen or a screen with 17/64 inch round openings.

% SML FLAT

Percentage by weight of shelled corn that passes through a 17/64 inch round screen and a 12/64 inch slotted screen, but does not pass through a screen with 15/64 inch round openings.

% SML ROUND

Percentage by weight of shelled corn that passes through a 17/64 inch round screen, but does not pass through a 12/64 inch slotted screen or a screen with 15/64 inch round openings.

% ROOT LODGE (RL)

Percentage of plants per plot leaning more that 30 degrees from vertical divided by, total plants per plot.

% STALK LODGE (SL)

Percentage of plants per plot with the stalk broken below the primary ear node divided by the total plants per plot.

DETAILED DESCRIPTION OF THE INVENTION

ZS03940 can be used as a female, having excellent seed production characteristics and good seed size. When placed in hybrid combination with males, particularly Lancaster types, this inbred forms excellent hybrids. In hybrid combinations this inbred can be used as a male. But due to this inbred's excellent seed yield it is infrequently used as a male, even though this inbred has good pollen shed. This inbred in hybrid combination, is a robust hybrid exhibiting very good early vigor, and excellent warm temperature tolerance.

The inbred has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information (Table 1) that follows. Most of the data in the Variety Description information was collected at Slater, Iowa or other Garst research stations.

The inbred has been self-pollinated for a sufficient number of generations to give inbred uniformity. During plant selection in each generation, the uniformity of plant type was selected to ensure homozygosity and phenotypic stability. The line has been increased in isolated farmland environments with data on uniformity and agronomic traits being observed to assure uniformity and stability. No variant traits have been observed or are expected in ZS03940.

The best method of producing the invention, ZS03940 which is substantially homozygous, is by planting the seed of ZS03940 and self-pollinating or sib pollinating the resultant plant in an isolated environment, and harvesting the resultant seed or the resultant pollen. The hybrid containing ZS03940 is best produced by planting the inbred ZS03940 and an appropriate crossing line in an isolated environment, detasseling one inbred and cross-pollinating with the pollen of the other inbred and harvesting the resultant seed or the resultant pollen.

                  TABLE 1     ______________________________________     ZS03940     VARIETY DESCRIPTION INFORMATION     Type: Dent     Region Best Adapted: Nebraska through Wisconsin. ZS03940     has a GRM 100.     Entomology:     ECB1 - 6.25 - Ratings scale 9 = highly resistant     ECB2 - 4.20 - 1 = highly susceptible     Maturity:     Days   Heat Limits     71-80   1456 - From planting to 50% of plants in silk     68-77   1387-1377 - From planting to 50% of plants in pollen     3-6    From 10% to 90% pollen shed     DISEASE RESISTANCE     Northern leaf blight = 6.5     Gray leaf spot = 3.3     GW = 6.0     MDMVB = 1.0     An Inbred comparable to ZS03940 is ZS01459.     ______________________________________     PLANT TRAITS        LEAF TRAITS     ______________________________________     PLANT HEIGHT               ˜70 IN.                         LEAVES ABOVE EAR                                        6-7     EAR HEIGHT               ˜28 IN.                         LEAVES BELOW EAR                                        5-6     BRACE ROOT               RED       LEAF ANGLE     SEMI-     COLOR               ABOVE EAR      ERECT     SHOOTS AT LEAFY     LEAF ANGLE     SEMI-     FLOWERING           BELOW EAR      ERECT     SILK COLOR               PALE      FLAG LEAF ANGLE                                        SEMI-               GREEN                    ERECT     COB COLOR DARK RED  LEAF COLOR     MEDIUM                                        GREEN                                        MEDIUM                                        GREEN     KERNEL ROWS               14-16     LEAF MARGIN    RED                         COLOR     ______________________________________     TASSEL              EAR AND     TRAITS              KERNEL TRAITS     ______________________________________     TASSEL SIZE               14 IN.    EAR LENGTH     6 IN.     NUMBER OF 4-5       EAR DIAMETER   1.4 IN.     BRANCHES     TASSEL    OPEN      COB DIAMETER   IN.     BRANCH     ANGLE     GLUME COLOR               GREEN     KERNEL CROWN   LIGHT               GREEN/    COLOR          YELLOW               PURPLE     ANTHER    YELLOW    KERNEL BODY    LIGHT     COLOR               COLOR          YELLOW     GLUME RING               RED     COLOR     PURPLE     ______________________________________                                    T-                N     MEAN    STD.  STAT  PROB  95% CI     ______________________________________     EAR HEIGHT 15    67.80   9.14  28.72 0.0000                                                (63.17,     (CM)                                       72.43)     LENGTH OF  15    88.40   2.32  147.3 0.0000                                                (87.22,     PRIMARY                                    89.58)     EAR LEAF (CM)     WIDTH OF   15    10.38   0.52  77.53 0.0000                                                (10.12,     PRIMARY                                    10.64)     EAR LEAF (CM)     TOP EAR    15    15.71   1.16  52.41 0.0000                                                (15.13,                                                16.30)     INTERNODE (CM)     DEGREE OF  15    27.60   3.33  32.06 0.0000                                                (25.91,     LEAF ANGLE                                 29.29)     # OF EARS  15    1.40    0.51  10.69 0.0000                                                (1.14,     PER PLANT                                  1.66)     # OF LEAVES                15    6.20    0.41  58.00 0.0000                                                (5.99,     ABOVE TOP EAR                              6.41)     # OF PRIMARY                15    3.40    0.91  14.47 0.0000                                                (2.94,     LATERAL                                    3.86)     TASSEL     BRANCHES     PLANT HEIGHT                15    195.4   13.35 56.68 0.0000                                                (188.6,     (CM)                                       202.1)     TASSEL LENGTH                15    36.47   3.76  37.58 0.0000                                                (34.56,     (CM)                                       38.37)     TASSEL BRANCH                15    70.73   27.44 9.98  0.0000                                                (56.85,     ANGLE                                      84.62)     # OF TILLER                15    0.07    0.26  1.00  0.3343                                                (-0.06,     PER PLANTS                                 0.20)     ______________________________________

The purity and homozygosity of inbred ZS03940 is constantly being tracked using isozyme genotypes as shown in Table 2.

Isozyme Genotypes for ZS03940

Isozyme data were generated for inbred corn line ZS03940 according to procedures known and published in the art. The data in Table 2 gives the electrophoresis data on ZS03940 and the comparison data on ZS01459. The inbreds differ in three locations.

                                      TABLE 2     __________________________________________________________________________     ELECTROPHORESIS RESULTS FOR ZS03940     __________________________________________________________________________     INBRED          ACP1              ACP4                  ADH                     MDH1                         MDH2                             PGD1                                 PGD2                                     PH1                                        PGM                                           IDH     ZS03940          11  33  22 11  22  11  11  22 22 11     INBRED          ACP1              ACP4                  ADH                     MDH1                         MDH2                             PGD1                                 PGD2                                     PH1                                        PGM                                           IDH     ZS01459          33  11  22 22  22  11  11  22 22 11     __________________________________________________________________________

Inbred and Hybrid Performance of ZS03940

The traits and characteristics of inbred corn line ZS03940 are listed to compare with other inbreds and/or in hybrid combination ZS03940 data shows the characteristics and traits of importance, giving a snapshot of ZS03940.

Table 3A compares inbred ZS03940 with inbred ZS01459. ZS03490 has better seedling vigor than ZS01459, and significantly greater plant and ear height. ZS03940 silks significantly later than ZS01459, showing significantly greater GDUs at all HEATS ratings. However, ZS03940 reaches HEAT PEEK with significantly less GDU's then ZS01459. ZS03940 shows significantly lower grain moisture at harvest and excellent inbred yields of 86.1 bushel per acre. Warm and cold germination ratings of both inbreds are similar. ZS03940 tends to produce larger kernels and thus less medium rounds and flats.

                                      TABLE 3A     __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                           PCT  PLANT                                     EAR         EAR   PCT     YEAR  INBRED                VIGOR EMERGE                           TILLER                                HEIGHT                                     HEIGHT                                          SHED   QUALITY                                                       BARREN     __________________________________________________________________________     OVERALL           ZSO3940                6.4   84.9      164.8                                     68.0 5.7           ZSO1459                6.1   81.6      152.7                                     61.4 5.7           # EXPTS                16    16        16   16   15           DIFF 0.3   3.2       12.1 6.6  0.1           PROB 0.325 0.322     0.002***                                     0.013**                                          0.792     __________________________________________________________________________     YEAR  INBRED                HEATP10                      HEATP50                           HEATP90                                HEATS10                                     HEATS50                                          HEATS90     __________________________________________________________________________     OVERALL           ZSO3940                1325  1373 1512 1415 1454 1495           ZSO1459                1339  1384 1468 1344 1381 1425           # EXPTS                15    15   15   15   15   15           DIFF 14    11   44   71   73   70           PROB 0.239 0.248                           0.070*                                0.000***                                     0.000***                                          0.001***     __________________________________________________________________________                           BL   % ROOT                                     % STALK                                          % DROPPED     YEAR  INBRED                HEATPEEK                      HEATBL                           MOIST                                LODGE                                     LODGE                                          EARS   MOISTURE                                                       YIELD     __________________________________________________________________________     OVERALL           ZSO3940                1274  2572 25.0                  12.2  86.1           ZSO14S9                1322  2400 31.0                  12.8  64.5           # EXPTS                15    2    1                     16    16           DIFF 48    172  6.0                   0.7   21.6           PROB 0.001***                      0.097*                     0.0059*                                                       0.000***     __________________________________________________________________________                WARM  COLD % LRG                                % LRG                                     % MED                                          % MED  % SML % SML     YEAR  INBRED                GERM  GERM ROUND                                FLAT ROUND                                          FLAT   ROUND FLAT     __________________________________________________________________________     OVERALL           ZSO3940                93.1  81.5           31.6 29.1           Z5O1459                92.3  79.1           39.0 28.1           #EXPTS                16    16             15   15           DIFF 0.8   2.4            7.3  1.0           PROB 0.497 0.550          0.000***                                          0.572     __________________________________________________________________________      *.05 < PROB <= .10      **.01 < PROB <= .05      ***.00 < PROB <= .01

Table 4 shows the GCA (general combining ability) estimates of ZS03940 compared with the GCA estimates of the other inbreds. The estimates show the general combining ability is weighted by the number of experiment/location combinations in which the specific hybrid combination occurs. The interpretation of the data for all traits is that a positive comparison is a practical advantage. A negative comparison is a practical disadvantage. The general combining ability of an inbred is clearly evidenced by the results of the general combining ability estimates. This data compares the inbred parent in a number of hybrid combinations to a group of "checks". The check data is from other companies' hybrids, particularly the leader in the industry and Garst's commercial products and pre-commercial hybrids which were grown in the same sets and locations.

Table 4 shows ZS03940 crossed in hybrid combinations and ZS01459 crossed in hybrid combination. ZS03940 shows yield by moisture (YM) advantage over ZS01459.

                                      TABLE 4     __________________________________________________________________________            N  FI                 YM GI                      I YLD                           MST                              % SL                                 % RL                                    % DE                                        TWT                                           POP                                              RM     __________________________________________________________________________     ZS03940 XR =            485               2.9                 0.5                    0.4                      0.7                        0.2                           1.1                              -0.2                                 0.2                                    0.1 -0.9                                           -2 101     ZS01459 XR =            2016               1.2                 0.1                    1.2                      0.9                        1.6                           0.0                              0.3                                 0.2                                    0.0 -0.8                                           -54                                              98     __________________________________________________________________________

Table 5 shows ZS03940, in a hybrid combination, in comparison with the plants in the environment around it at the same location. ZS03940 in hybrid combination yields well in low to medium yielding environments. In these yielding environments ZS03940, in hybrid combination, out yields ZS01459 as a hybrid. In high yielding environments, ZS03940 hybrid tends to show less aggressive yields compared to the environment.

                  TABLE 5     ______________________________________     YIELD RESPONSE     ______________________________________     1.       HYBRID     YIELD              Environment                         75   100  125   150   175   200              ZS03940/X  88   110  131   152   173   194     2.       HYBRID     YIELD              Environment                         75   100  125   150   175   200              ZS01459/X  81   105  130   154   179   203     ______________________________________

Table 6A shows the advantage ZS03940 hybrid has compared to one commercially available Garst hybrid. The ZS03940 hybrid is significantly better in yield/moisture and shows a positive moisture advantage compared to ZS01459.

                                      TABLE 6A     __________________________________________________________________________     PAIRED HYBRID COMPARISON DATA     __________________________________________________________________________                 % ROOT                       % STALK                            % DROPPED                                   TEST     YEAR  HYBRID                 LODGE LODGE                            EARS   WEIGHT                                        MOISTURE                                              YIELD                                                  GI     __________________________________________________________________________     OVERALL           ZSO3940/X                 0.4   4.5  0.1    47.0 21.3  141.6                                                  166.2           8771  0.2   4.9  0.1    46.9 22.4  140.3                                                  165.3           # EXPTS                 42    42   42     37   42    42  42           DIFF  0.2   0.5  0.0    0.1  1.2   1.3 0.9           PROB  0.144 0.569                            0.976  0.873                                        0.001***                                              0.517                                                  0.504     __________________________________________________________________________     YEAR  INBRED                 MATURITY                       Y M  FI     __________________________________________________________________________     OVERALL           ZSO3940/X                 .     7.2  117           8771  .     6.6  114           # EXPTS                 .     42   42           DIFF  .     0.5  3.5           PROB        0.001***                            0.023**     __________________________________________________________________________      *.05 < PROB <= .10      **.01 < PROB <= .05      ***.00 < PROB <= .01

Table 6B shows the advantages and disadvantages generated by comparison of the agronomic data of the two hybrids. ZS03940 brings its vigor into the hybrid package.

                  TABLE 6B     ______________________________________     ZS03940/INBRED/X vs. 8771     AGRONOMIC DATA                             VI-  PLANT  EAR    STAY-     HYBRID   N     ESTAND   GOR  HEIGHT HEIGHT GREEN     ______________________________________     Advantage of              20    -9.5     0.1  -2.7   -4.1   1.2     ZS03940/X     over 8771     ______________________________________

Table 6C shows the excellent plant integrity that ZS03940, in hybrid combination carries. 8771 and ZS03940/X both have a common inbred line.

                  TABLE 6C     ______________________________________                                 CORN                                 ROOT WORM                                          PLANT             ECB1      ECB2      DAMAGE   INTEGRITY     HYBRID  RATING    RATING    RATING   RATING     ______________________________________     ZS03940/X             6.0       --        3.8      6.6     8771    6.2       4.7       4.3      3.9     ______________________________________

The inbred ZS03940 can be employed as the female or male plant in a hybrid production field. This inbred is a vigorous line with excellent inbred seed yield. ZS03940, in hybrid combination, produces hybrids that have early vigor and yet have plant integrity. The ZS03940 hybrid has strong seedling emergence and vigor. Yield levels excellent in environments that are low to medium and acceptable in high regions. ZS03940 inbred has good general combining ability.

The foregoing is set forth by way of example and is not intended to limit the scope of the invention.

This invention also is directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant wherein the first or second parent corn plant is an inbred corn plant from the line ZS03940. Further, both first and second parent corn plants can come from the inbred corn line ZS03940. A variety of breeding methods can be selected depending on the mode of reproduction, the trait, the condition of the germplasm. Thus, any such methods using the inbred corn line ZS03940 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, haploid and anther culturing and the like.

Various culturing techniques known to those skilled in the art, such as haploid, transformation, and a host of other conventional and unconventional methods are within the scope of the invention. All plants and plant cells produced using inbred corn line ZS03940 are within the scope of this invention. The invention encompasses the inbred corn line used in crosses with other, different, corn inbreds to produce (F1) corn hybrid seeds and plants. This invention includes cells which upon growth and differentiation produce corn plants having the physiological and morphological characteristics of the inbred line ZS03940.

Duncan, from at least 1985-1988 produced literature on plant regeneration from callus. Both inbred and hybrid callus have resulted in regenerated plants at excellent efficiency rates. Somatic embryogenesis has been performed on various maize tissue such as glume which before the 1980's was considered unusable for this purpose. The prior art clearly teaches the regeneration of plants from various maize tissues.

European Patent Application, publication 160,390, describes tissue culture of corn which can be used by those skilled in the art. Corn tissue culture procedures are also described in the literature as early as 1982.

A deposit of at least 2500 seeds of the inbred seed of this invention is maintained by Garst, 2369 330th Street, Slater, Iowa 50244. Access to this deposit will be available during the pendency of this application to the Commissioner of Patents and Trademarks and persons determined by the Commissioner to be entitled thereto upon request. All restrictions on availability to the public of such material will be removed upon issuance of any claims in this application by depositing at least 2500 seeds of this invention at the American Type Culture Collection, Rockville, Md. The deposit of at least 2500 seeds will be from inbred seed taken from the deposit maintained by Garst. The ATCC deposit will be maintained in that depository, which is a public depository, for a period of 30 years, or 5 years after the last request, or for the effective life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period.

Information on some ZS designations may be available from the PVP office.

Accordingly, the present invention has been described with some degree of particularity directed to the preferred embodiment of the present invention. It should be appreciated, though, that the present invention is defined by the following claims construed in light of the prior art so that modifications or changes may be made to the preferred embodiment of the present invention without departing from the inventive concepts contained herein. 

We claim:
 1. Inbred corn seed designated ZS03940, some of said seed deposited in the ATCC and designated accession number X.
 2. A corn plant produced by the seed of claim
 1. 3. A tissue culture of regenerable cells of ZS03940 of claim 2 wherein the tissue regenerates plants having the genotype of ZS03940.
 4. A tissue culture according to claim 3, the tissue culture selected from the group consisting of leaves, pollen, embryos, roots, root tips, anthers, silk, flowers, kernels, ears, cobs, husks and stalks, and cells and protoplasts thereof.
 5. A corn plant having all of the physiological and morphological characteristics of ZS03940 regenerated from the tissue culture of claim
 3. 6. Hybrid seed produced by:(a) planting, in pollinating proximity, seeds according to claim one of corn inbred lines ZS03940 and another inbred line, one of said inbred lines not releasing pollen; (b) cultivating corn plants resulting from said planting; (c) allowing natural cross pollination to occur between said inbred lines; and (d) harvesting seeds produced on the non pollen releasing inbred.
 7. Hybrid seed produced by hybrid combination of plants of inbred corn seed designated ZS03940 in claim 1 and plants of another inbred line.
 8. Hybrid plants grown from seed of claim
 7. 9. A first generation (F1) hybrid corn plant produced by using ZS03940 according to claim 1 the process of:(a) planting seeds of corn inbred lines ZS03940 and another inbred line; (b) cultivating corn plants resulting from said planting; (c) preventing pollen production by the plants of one of the inbred lines; (d) allowing pollination to occur between said inbred lines; (e) harvesting seeds produced on plants of the inbred line of step (c); and (f) growing a harvested seed of step (e).
 10. A tissue culture of the regenerable cells of the corn plant of claim
 8. 11. A tissue culture of the regenerable cells of the corn plant of claim
 9. 12. An inbred corn plant with all of the phenotypic, physiological and morphological characteristics of inbred corn line of claim
 2. 